Cubic zirconia is probably the most commonly known diamond alternative. CZ is often found in childrenās and costume jewelry, but it is sometimes used in placeholder and lower quality engagement rings. It is an artificially produced version of the element zircon. Colorless CZ is common, but its brilliance is easily diminished when it gets dirty. It weighs almost twice as much as a diamond, and, like moissanite, has a lot of fire. It is often cut with larger facets to make the fire less noticeable, but those large facets can also make it look more artificial. CZ has good hardness, but it scratches more easily than a diamond.